In the last 10 years there has been an abundance of new epidemiological studies on health effects of particulate air pollution. The overall evidence suggests that fine particulate pollution can be an important risk factor for cardiopulmonary disease. Long-term, repeated exposure to fine particulate air pollution may increase the risk of chronic respiratory disease and the risk of cardiopulmonary mortality. Short-term exposures exacerbate existing cardiovascular and pulmonary disease and increase the risk of becoming symptomatic, requiring medical attention, or even dying. This paper outlines the results of the basic epidemiologic studies and briefly reviews and discusses recent studies that have looked at specific physiologic health endpoints in addition to lung function.